1. Field of the Invention
This invention relates generally to turf care equipment, and more particularly to a system for regulating the operation of a hydrostatic drive of a turf care machine by selectively controlling neutral, reverse and forward modes of the hydrostatic drive with a minimum number of components.
2. Discussion
Conventional commercial walk-behind turf care machines, such as walk-behind lawnmowers and self-propelled vacuum systems, include a number of levers and linkages used to control machine operation. During routine operation, these machines must often be maneuvered around trees, flower beds and other obstacles quickly and with precision. Because these machines typically weigh several hundred pounds, it would be labor intensive, if not impossible, to operate and maneuver the turf care machines in such a manner for extensive periods of time without some type of operator assist device.
Therefore, commercial turf care machines are typically equipped with self-propelling drive mechanisms for driving the wheels of the machines. These drive mechanisms typically include a mechanism for transferring the driving torque from a source of power such as an internal combustion engine to at least two of the machine wheels, thereby turning the machine wheels and assisting the machine operator in both propelling and maneuvering the piece of equipment.
While both hydraulic and mechanical drive mechanisms have been commonly used in the past, hydrostatic drive mechanisms are being implemented in walk-behind turf care machines on an ever increasing basis due to the decrease in price of such systems. Hydrostatic drive mechanisms have long been known to exhibit desirable characteristics such as allowing a machine operator to quickly switch among forward, neutral and reverse modes of operation.
A turf care machine operator manipulates a typical hydrostatic drive mechanism through a plurality of levers located on an operator/turf machine interface such as a pair of handle bars. These operator control systems typically include both traction and speed controls and enhance machine operability and maneuverability. A typical traction control provides the machine operator with selective control among forward, neutral and reverse modes of operation, while a typical speed control provides the operator with a control for regulating the maximum forward speed at which the machine can be operated. Typical speed controls allow reverse operation to occur even when the speed control is set to neutral and do not limit the maximum reverse speed. State-of-the art traction and speed controls are disclosed in the publicly available Ransomes Parts Manual P/N 38422C dated February 1994.
While present hydrostatic drive operator control systems such as those described above exhibit sufficient performance characteristics, such systems require numerous linkages between the components to implement, thus increasing turf care machine cost. It is also desirable to provide more ergonomic arrangements for the operator controls to facilitate ease of operation and provision of operation instructions.
Also, due to increasing international sales and the nature of such equipment, it has become increasingly important to include graphical instruction symbols on the machine in a location readily discernible to the operator.
Therefore, it is an object of the present invention to provide an improved system for regulating/controlling a drive mechanism of a conventional turf care machine.
It is an additional object of the present invention is to provide a system for regulating/controlling the hydrostatic drive system of a turf care machine that allows the operator to limit the maximum reverse speed and helps prevent inadvertent reverse operation when the speed control is in neutral.
It is a further object of the present invention to provide a system for regulating/controlling the hydrostatic drive of a turf care machine that has parts having multiple system functions, thereby minimizing the number of linkages and parts in such a system.
It is also an object of the present invention to provide an ergonomically efficient operator station providing the operator with easy access to machine controls, and with readily visible instruction symbols.